1=pod 2 3=head1 NAME 4 5BN_CTX_new, BN_CTX_init, BN_CTX_free - allocate and free BN_CTX structures 6 7=head1 SYNOPSIS 8 9 #include <openssl/bn.h> 10 11 BN_CTX *BN_CTX_new(void); 12 13 void BN_CTX_free(BN_CTX *c); 14 15Deprecated: 16 17 void BN_CTX_init(BN_CTX *c); 18 19 20=head1 DESCRIPTION 21 22A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by 23library functions. Since dynamic memory allocation to create B<BIGNUM>s 24is rather expensive when used in conjunction with repeated subroutine 25calls, the B<BN_CTX> structure is used. 26 27BN_CTX_new() allocates and initializes a B<BN_CTX> 28structure. 29 30BN_CTX_free() frees the components of the B<BN_CTX>, and if it was 31created by BN_CTX_new(), also the structure itself. 32If L<BN_CTX_start(3)|BN_CTX_start(3)> has been used on the B<BN_CTX>, 33L<BN_CTX_end(3)|BN_CTX_end(3)> must be called before the B<BN_CTX> 34may be freed by BN_CTX_free(). 35 36BN_CTX_init() (deprecated) initializes an existing uninitialized B<BN_CTX>. 37This should not be used for new programs. Use BN_CTX_new() instead. 38 39=head1 RETURN VALUES 40 41BN_CTX_new() returns a pointer to the B<BN_CTX>. If the allocation fails, 42it returns B<NULL> and sets an error code that can be obtained by 43L<ERR_get_error(3)|ERR_get_error(3)>. 44 45BN_CTX_init() and BN_CTX_free() have no return values. 46 47=head1 SEE ALSO 48 49L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)>, 50L<BN_CTX_start(3)|BN_CTX_start(3)> 51 52=head1 HISTORY 53 54BN_CTX_new() and BN_CTX_free() are available in all versions on SSLeay 55and OpenSSL. BN_CTX_init() was added in SSLeay 0.9.1b. 56 57=cut 58